Matthew Keys, 26, who was under suspension from his post as deputy social media editor at the news agency, said that the charges against him had not been mentioned during a telephone call by Reuters in which his employment had been terminated on Monday. Instead, he said that the company had told him that it was because he had violated a final written warning.

He later said that one of the reasons given for termination had been his independent coverage of the events in Boston last week, when he tweeted information gleaned from police scanners and which later turned out to be incorrect. Anthony De Rosa, Reuters social media editor, had retweeted warnings by police for information from the scanners not to be posted online and, while not naming Keys, had personally tweeted at one stage: "Get off the scanners folks, be smart."

"It's my understanding that Reuters did not agree with some of the coverage I did on my own during the Boston Marathon events from last week," Keys told the Politico website.

"And they have a specific set of reasons for the termination which I don't agree with and the union that represents me does not agree with. We are in agreement, the union and myself, that I have done nothing wrong, that the basis for the termination is incorrect and doesn't hold any water."

A spokesman for Reuters confirmed that Keys had been sacked but declined to provide any further comment.

Keys is accused of supplying Anonymous with log-in credentials for a Tribune Company computer server. Keys, who was a former employee of television station owned by Tribune company, denies the charges.

A Reuters spokeswoman has previously pointed out that the alleged action occurred more than a year before Keys joined Reuters, which has not linked the issue to his sacking.

Keys said that "one has to wonder" if the charges were connected to his termination, telling Politico: "I can only say that I assume it is, that I assume they were looking for an out."